The invention relates to a method for operating a liquid ring machine, as well as to a liquid ring machine for implementing the method.
In the case of a liquid ring machine disclosed by German Patent C 961 653, the working chamber is subdivided by a wall part that axially subdivides the impeller and by an intermediate wall of the housing shell arranged in the same plane with this wall part into two partial working chambers of the same size. During operation, a liquid ring forms in each partial working chamber.
Separate suction and discharge connections are assigned to each partial working chamber. In addition, the partial working chambers are interconnected in the lower region by openings, making it possible for both partial working chambers to be drained simultaneously through a shared outlet. A pump of this type is able to deliver two distinct gases having different pressures at the same time.
The CH-A 285 570 discloses a two-stage liquid ring pump, whose first stage is designed for a larger output volume than its second downstream stage. Such pumps generally experience difficulties when they have to work at a low vacuum.
In this case, the output volume of the first stage is substantially greater than that of the second stage. The second stage is not able to process the volume required by the first stage. As a result, blocking occurs, which reduces pump efficiency and can also cause damage to the pump. This working point has to be run through at every start-up operation of the pump. For this reason, it is provided in the case of this known pump for the second stage (high pressure stage) to be made inactive by removing operating liquid for so long until the ratio of the intake volume to the final volume corresponds to the ratio of the output volume of the first stage to that of the second stage. So much operating liquid is removed from the second stage, that its delivery is interrupted. Thus, the liquid ring, which requires a corresponding amount of energy for its actuation, still remains in the second liquid stage.
This invention is directed to a method of adapting a liquid ring machine to various types of loading and to provide a liquid ring machine for implementing this method.